Breathing apparatus are used with interfaces to supply a flow of breathing gases to users. Connectors are used to join the breathing apparatus to the interface. In many applications, the connectors used to join the breathing apparatus to the interface include proprietary connectors such that the interface of one company will not connect to the breathing tube, which is connected to the breathing apparatus, of another company. In some applications, a standard connector can be used on the end of the breathing tube. For this reason, care provides typically stock multiple configurations of interfaces to ensure that the selected interface can be joined to the breathing tube.